Summing Amplifier

This is the configuration of "summig amplifier".Which perform addition of all are inputs.if we applying three input 1] 1v --- 2]1v |-> input signals(all three) 3] 1v --- so, in result we get the addition on these three input signal. *****required thing ***** -> here Rf and Rin must be same ( where Rin=R1=R2=R3) *****formula********** Vout= Rf/Rin[v1+v2+v3] {where R=R1=R2=R3}